One could argue that, and like I just wrote in my reply to your sibing comment (https://www.hackerneue.com/item?id=46087142) I would agree with you with regards to ethics, but it's not a valid argument from an actual legal perspective.
I'd love to be proven wrong about this, because I'm not blowing smoke up your ass I really do agree with you in that I wish MS could and would be sued over this, and lose, and have to stop making Windows shit like this. But I'm fairly confident that the only possibility would be for EU (or individual nations) to write new legislation addressing it.
One could argue that adding ads after some time from a system putchased without ads throuh updates is a defect that has been hidden at purchase time.